Deyn saves Casian after a crash that destroys her family, and for a long time, the only thing that can distract Casian from those memories is the sound of Deyn’s voice. But Deyn is a starship, from a race of organic ships that call themselves angels, and her voice isn't for everyone.

Most ships speak to only one person: their captain, the human partner who recruits and supervises the crew. When Deyn breaks tradition to talk directly to a survivor being given safe passage to the nearest port, everyone notices. The nearest port comes and goes, and Casian does not.

Deyn’s crew welcomes Casian, and the captain gives her substantial leeway in light of the ship's favoritism. The ships-in-service program that manages Deyn and her kind isn't so sanguine, but Deyn gets what she wants.

Now it's up to Casian to turn the second chance into a real life, free of the ghosts of her past, while trying not to upset the delicate balance between humans and angels.